Bellows forming machine



April 18, 1967 J P Y O ET AL 3,314,276

BELLOWS FORMING MACHINE Filed April '7, 1964 5 Sheets-Sheet 1 iNVENi'ORSBY A401. Mass/wee fie, M Z

April 18, 1967 J PEYTON ET AL BELLOWS FORMING MACHINE 3 Sheets-Sheet 2Filed April '7, 1964 INVENTORS g c/ZAWF. as 701v PAUL Mam/2 MW a/muzlApril 18, 1967 J PEYTON ET AL 3,314,276

BELLOWS FORMING MACHINE Filed April 7, 1964 5 Sheets-Sheet 5 l v e 5290,2 9. .140

15a 25a; L 150 A sa INVENTOR5 c/omvFPe /ro/v BY Ava; I ZFISSNEE W WM agmM A rme/vzys United States Patent 3,314,276 BELLOWS FQRMING MACHINE JohnF. Peyton, Long Beach, and Paul Wassner, Anaheim, Calif., assignors toFederal-Mogul-Bower Bearings, Inc., Detroit, Mich, a corporation ofMichigan Filed Apr. 7, 1964, Ser. No. 358,042 14 Claims. (Cl. 72-370)The present invention relates generally to a method and apparatus forforming annular corrugations or convolutions in the walls of tubularbodies, and more particularly, to an improved method of making so'calledmetal bellows of the kind now extensively used in connection withthermostats and pressure-operated devices, valves, flexible, corrugatedtubular conduits, fittings and the like articles.

This invention finds its most important application in connection withthe manufacture of relatively large diametered, flexible, metalconduits, connections and the like piping devices for carrying variousfluids.

Heretofore, in the manufacture of such metal bellows, or bellows typepipes, fittings, and the like'devices, various means have been employedfor forming the circumferential annular folds or convolutions in thewalls of a tubular work piece, such means including the employment ofhigh hydraulic pressures internally of the tubular work piece -tostretch a portion of the tubular walls into conformity with a suitablyformed annular die, the employment of one or more annular-shaped rambodies for drawing the tubular stock into suitably-shaped die bodies, orthe use of various kinds of roller presses for rolling the convolutions,usually in a plurality of stages. In all of such mechanical or hydraulicsystems heretofore employed, the nature of the forming processes usuallyrequire a portion of the metal of the tubular work piece to be drawn orstretched over the edges of the forming tools, thereby subjecting themetal, not only to sharp bending and stretching action resulting in workhardening of the material, but also resulting in surface marring whichis injurious not only to the appearance but to the strength and fatiguelife of the finished article. The machines heretofore employed in theprocess of manufacture of such metal bellows articles and devices havealso often 'been excessively massive, extremely expensive, and lackingin durability.

It is accordingly an object of this invention to provide an improvedmethod of and apparatus for manufacturing flexible metal bellows and thelike flexible tubular articles.

It is still another object of this invention to provide a flexible metalbellows manufacturing machine which is capable of manufacturing metallicbellows of improved quality.

It is a further object of this invention to furnish a metal bellowsmanufacturing machine capable of producing such 'bellows free fromdetrimental surface abrasions and scratches.

It is a further object of this invention to furnish an improved methodand apparatus for forming metal bellows of improved uniformity anddimensional precision than heretofore usually possible.

It is a still further object of this invention to provide a machine forforming metal walled flexible bellows articles which are relatively freefrom inconsistencies and variations in hardness and elasticity andhaving relatively improved operating and durability characteristics.

It is a still further, important object of this invention to provide amethod and apparatus for formation of metal bellows from low ductilitymetals which heretofore have been considered difficult, if notimpracticable for such use, such as for example, stainless steel,certain high hardness aluminum alloys, titanium, and the like.

3,314,276 Patented Apr. 18, 1957 ice These and other objects andadvantages, and features of the novelty will be evident hereinafter.

'In the drawings which show a presently preferred embodiment of theinvention and in which like reference characters designate the same orsimilar parts throughout the several views:

FIGURE 1 is a view, partly in elevation and partly in vertical section,of the general assembly of the bellows forming machine of the invention.

FIGURE 2 is a horizontal, sectional view taken on line 2-2 of FIGURE 1.

FIGURE 3 is a fragmentary, side elevational view of a portion of theapparatus of FIGURE 2 as viewed from line 3-3, with portions of theapparatus remover for clarity of viewing.

FIGURE 4 is an enlarged, fragmentary, cross-sectional view taken on line44- of FIGURES 1 and 2.

FIGURE 5 is an enlarged, fragmentary, vertical sectional view of thatportion of the apparatus withinbroken lined circle A of FIGURE 1,illustrating the initial relative positions of the forming tool elementsand the work piece, in readiness for commencement of a bellows cnvolution forming cycle of operation.

FIGURE 6 is a view of the same forming tool elements shown in FIGURES 1and 5, illustrating their relative positions at an initial stage in thebellows convolution forming cycle of operation.

FIGURE 7 is a view of the same forming tool elements shown in FIGURES land 5, but showing the relative positions thereof at a second stage inthe progress of the bellows convolution forming cycle.

FIGURE 8 is a view of the same forming tool elements shown in FIGURES land 5, but showing the relative positions thereof at a third stage inthe progress of the bellows convolution forming cycle.

FIGURE 9 is a view of the same forming tool elements shown in FIGURES 1and 5, but showing the relative positions thereof at a fourth stage inthe progress of the bellows convolution forming cycle.

FIGURE 10 is a view of the same forming tool elements shown in FIGURES 1and 5, but showing the relative positions thereof at a fifth stage inthe progress of the bellows convolution forming cycle with the bellowsconvolution in completed form and with the work piece in readiness forvertical movement to a new position for formation of another bellowsconvolution.

FIGURE 11 is a view of the same forming tool element shown in FIGURES 1and 5, but showing the positions thereof at a sixth and final stage ofthe bellows convolution forming cycle of operation, showing the bellowsconvolution in completed form and with the work piece moved to a newposition corresponding to that shown in FIGURES 1 and 5, in readinessfor initiation of the repetition of the forming cycle for anotherbellows convolution.

Referring first primarily to FIGURES 1 and 2, the machine assembly has aprincipal supporting structure or framework comprising a stationary,rectangular top platform 10 having a circular central opening 12therein, a stationary rectangular lower base platform 14, also having acircular central opening 16 therein coaxial with opening 12, and fourvertical, cylindrical supporting column members 18, 20, 22 and 24 whichsupport the top platform 19 and the lower base platform 14, invertically elevated and fixed spaced-apart relation. The four columnmembers are attached to the platforms 10 and 14 by suitable attachmentmeans located adjacent the four corners thereof. The lower ends of thesupporting column members 18, 2Q, 22 and 24 extend below the corners ofthe lower base platform 14 a suitable elevational distance as shown at26 and 28, and are provided at their lower ends with suitable baseflanges as shown at 30 and 32 for support of the weight of the apparatusassembly on a suitable surface 34.

The top platform 10 serves operatively to support a split die mechanismshown generally at 139, as hereinafter more fully described.

Supported parallel to and adjacently beneath the top platform 10 is agenerally rectangular, vertically movable, intermediate platform 36having a central opening 38, coaxial with openings 12 and 16, andprovided adjacent its corners with guide openings 42, 44, 46 and 48,through which the beforementioned supporting column members 18, 29, 22and 24 respectively guidingly extend. In operation, the intermediateplatform 36, hereinafter referred to as the follower die supportingplatform serves to vertically movably support an annular follower diemember 128 as is hereinafter more fully described. The follower diesupporting platform 36 is supported for limited vertical movementrelative to the top platform 10 by means of four hydraulic actuators 58,52, 54, and 56, each of which comprises a cylinder 58 containing in itsbore a piston 60 and from which extends a plunger 62, as best shown inFIGURE 1.

The lower ends of each of the cylinders 58 are fixedly supported uponbrackets as shown at 64 which are attached to the column members 18, 20,22 and 24, and the plungers 62 are attached at their upper ends tocorner portions of the follower die supporting platform 36 adjacent thebeforementione guide openings 42, 44, 46 and 48 therein.

The cylinders 58 are provided at opposite ends thereof with ports whichenter the opposite ends of the cylinder bores on opposite sides ofpistons 62, and to which hydraulic pressure connections are made, asshown at 66 and 68, for simultaneously raising and lowering the plungers62 and the follower die supporting platform 36 carried thereby, as willbe described hereinafter in connection with the operation of theapparatus.

Supported for vertical movement between the follower die supportingplatform 36 and the base platform 14 is a generally rectangular-shapedwork elevator and indexing table 70 having a central circular opening 72therein coaxial with the beforementioned openings 12, 16 and 38, Thework elevator and indexing table 70 is supported for controlled verticalmovement by four vertical, externally threaded, elevator spindles 74,76, 78, and 80 which pass through and make threaded engagement withthreaded nut bearings attached to the elevator table 70 adjacent thecorners thereof as shown at 82 and 84. The elevator spindles 74, 76, 78and 80 are rotatably supported adjacent their lower ends upon the baseplatform 14 by means of thrust bearings, two of which are in view at 86and 88 in FIGURE 1. The lower ends of each of the elevator spindles 74,76, 78 and 80 are provided with integral extension shafts which passthrough the thrust bearings and extend below the base platform as shownat 90 and 92 in FIGURE 1.

Fixed on each of the extension shafts of the elevator spindles 74, 76,78 and 80 are chain sprockets 94, 96, 98 and 100 respectively, allrotatably linked together for simultaneous rotation by means of anencompassing, continuous link chain 182. One of the extension shafts,for example, that shown at 90 in FIGURE 1, carries an additional chainsprocket 104 which is drivingly connected by means of link chain 106 toa sprocket 108 carried on :he drive shaft of a motor 110 which ispreferably of 1 positive displacement hydraulic type. In the operation3f the apparatus, the chain sprocket 104 is driven by notor 110, therebysimultaneously driving the chain iprockets 94, 96, 98 and 100 and thecorresponding elevaor spindles 74, 76, 78 and 8G. The motor 110 issuitibly mounted upon a bracket 112 which is bolted to the inder surfaceof the base plate 14.

The upper ends of the elevator spindles 74, 76, 78 and K extendrotatably and relatively axially slidable through :learance openings, asshown at 114 and 116, extending through the follower die supportingplatform 36, with the upper ends of the spindles rotatably journaled inbearings, as shown at 118 and 120, fixed to a portion of the lowersurfaces of the top platform 10. The work elevator table is providedwith a plurality of vertical, upwardly extending indexing pins 122. Theindexing pins 122 may have any suitable arrangement in table 70 toaccommodate the size and shape of the work piece upon which formingoperations are to be performed, but in the present apparatus, they arepreferably arranged circumferentially spaced-apart, on a circle, coaxialwith the beforementioned opening 72 and having a diameter slightly lessthan the internal diameter of the tubular work piece. The work piece 124is thereby positioned vertically in the apparatus with its lower endcentered and supported on the work elevator table 70, surrounding thebeforementioned pins 122.

Seated in a depressed, upwardly facing annular groove 126, formedcoaxially around the inner marginal portioning of the beforementionedcentral opening 38 in the follower die supporting platform 36, is anexternal, generally annular-shaped die member 128 hereinafter referredto as the follower die. The follower die 128 is formed with a central,upstanding, annular collar portion 130 having a coaxial bore 131 which,in the present instance, has an internal diameter which makes a slidablefit with very slight clearance around the exterior surface of thetubular work piece 124.

Attached to the underside of the top platform 10 and comprising aportion of the beforementioned split die mechanism 139 is a pair ofelongated, transversely extending, parallel slide guides 134 and 136,and slidably supported in said guides against the under side of the topplatform 10 are a pair of oppositely positioned split die carrier plates138 and 140. The inner, adjacently confronting edge portions of thesplit die carrier plates 138 and 140 are semi-circular in form, as shownat 142 and 144, whereby, when they are slidingly closed together in theguides 134 and 136 in end-to-end abutment with one another, they form aclosed circular opening therebetween which, in the present instance,coaxially encircles the tubular work piece 124. The split die carrierplates 138 and 140 are formed around their inner semi-circular edgeswith radially inwardly extending, round-edged, coaxial die elements 146and 147 respectively of reduced thickness which, when the die carrierplates 138 and 140 are in closed position, form in effect a relativelythin split annular die ring. The thickness of the thus formed split diering and the radius of curvature of the inner edge thereof is made tocorrespond approximately to the desired spacing between and the radiusof curvature of the inner edges of the convolution to be formed in thetubular work piece.

Pin connected to the outer end edges of the split die carrier plates 138and 140, by means of pin fittings, as shown at 148 and 150 respectively,are a pair of laterally extending, split die actuator rods 152 and 154.The outer end portions of the split die actuator rods 152 and 154 areexternally threaded as shown at 156 and 158, and are operatively coupledfor reciprocable motion, to split die actuator jacks shown generally at157 and 159. The split die actuator jacks 157 and 159 are provided withinternally threaded drive nuts 160 and 162 which make threadedconnection with the externally threaded portions of the actuator rods152 and 154 which are, in turn, drivingly coupled through suitable wormgear drives 164 and 166 to hydraulic motors 168 and 170. The housingsfor the internally threaded drive nuts 160 and 162, together with theirworm gear drive elements 164 and 166, and the hydraulic motors 168 and170 are supported outboard of the top platform 10 and in alignment withthe actuated rods 152 and 154, by means of brackets 172 and 174 whichare attached at their inner ends to the upper marginal portions of thetop platform 10 by suitable means such as bolting or welding.

Fixed to and supported upon the central portion of the base platform 14coaxial with the opening 16 therein, and coaxial with the openings 12and 38 in the top plat form 19 and follower die platform 36, is avertically extending guide tube 176. Axially slidable within the guidetube 176 is a tubular supporting column 178 which carries upon its upperend an internal expansion die mechanism assembly shown generally at 180.The lower end of the tubular supporting column 178 is coaxially fixed toa flanged fixture 182 which is in turn fixed to the central portion of arectangular shaped, expansion die assembly supporting plate 184.

The supporting plate 184 is vertically, resiliently and adjustablysupported adjacent its four corners upon four adjustable, verticallyresilient supporting means 185 each comprising an external helicalspring 186 which contains within it a hollow, resilient, expansible aircushion 188. The lower ends of the helical springs 186 and air cushions188 are supported upon a rectangular elevator frame 190 which is in turnvertically, adjustably supported at its four corners upon fourjack-screws 192, which extend upwardly from four jack-screw mechanisms,two of which are in view and generally indicated at 196 in FIGURE 1. Allfour of the jack-screw mechanisms 196 are adapted to be simultaneouslydriven at the same rate through a system of interconnected shafts andgear boxes, a portion of which are shown at 200, 202, and 204, by meansof a motor 206 which is preferably of a positive displacement hydraulictype. The jack-screw mechanisms 196 are supported by means of baseflanges 208 upon the beforementioned surface 34.

A limit switch 209 attached to a fixed support 211 and positionedadjacent the rectangular elevator frame 190 is provided as a part of theelectrical control circuit, not shown, for the motor 206. The switchinclude a toggle arm 213 which is coupled to a switch mechanism withinthe housing of the switch such that the electrical circuit to the motoris opened, thereby de-energizing the motor at upper or lower pivotalpositions of the toggle arm. The toggle arm is positioned to be actuatedby upper and lower stops 215 and 217 adjustably positioned on a rod 219which is attached to the adjacent end of the frame 190. Predeterminedupper and lower limit of travel of the frame 199 is thus determined asrequired for the bellows convolution forming cycles of the forming dyes.

Supported by and extending axially downwardly from the underneath sideof the suporting plate 184 is a hydraulic expansion die actuatingcylinder 212 having inlet and outlet port connections 214 and 216entering the upper and lower ends respectively of the bore thereof.Axially, slidably contained within the bore of the actuating cylinder212 is an expansion die actuating piston 218 to which is connected apiston rod 220 and which extends coaxially upwardly through the upperend of the cylinder through a suitable piston rod seal 222. The upperend of the piston rod 220 is threadedly connected at 224 with the lowerend of an expansion die actuating push-pull rod 226 which extendsupwardly, coaxially within the supporting column 178 and makes fixedconnection adjacent its upper end with a downwardly tapered,frustoconical expansion actuator wedge 230, which comprises a portion ofthe beforementioned internal expansion die mechanism assembly showngenerally at 180.

Also included within the internal expansion die mechanism assembly 180is an expansion die supporting head 232 which includes a downwardlyextending cylindrical seat portion 234 which makes telescopic supportingengagement at 236 within the upper end of the beforementioned supportingcolumn 17 8 and which carrie an upper, generally annular, expansiondie-carrier supporting flange 238. Radially, slidably supported upon theupper surface of the supporting flange 238 upon radial dovetail guides,as best shown at 240 in FIGURE 4, are a plurality of circumferentiallyadjacently positioned, die carrier sectors 242 to 264 as shown in FIGURE2, and two of which are also shown at 250 and 264 in FIGURE 1. Each ofthe expansion die carrier sectors carries fixed adjacent its radiallyouter edge, an expansion die element as shown at 266 to 288 in FIGURE 2and two of which are in view in elevation at 278 and 288 in FIGURE 1.Each of the expansion die elements 266-288 carries an integrally formed,outwardy extending, relatively thin, roundedged, arcuate die segment,:as shown at 290 and 292 in FIGURE 1. The thickness of each of the diesegments and the radius of curvature of the outer edges thereof are madeto correspond approximately to the desired spacing between and theradius of curvature of the edges of the convolutions to be formedthereby in the tubular work piece.

An annular shaped, helically wound, garter spring 294 encircles theupstanding portions of the expansion die carrier sectors 242-264 andserves to bias or urge the expansion die carrier sectors and theexpansion die elements carried thereby toward their most radiallyinwardly retracted positions relative to the expansion die carriersupporting flange 238 and the dovetail guides 240 thereon. The radiallyinner sides of each of the expansion die carrier sectors 242-264 isformed with a downwardly convergingly, circumferentially curved surfacewhich closely matches the downward tapering frustoconical exteriorsurface of the actuating wedge 230 upon which they slidingly bear, andthese surfaces are retained in sliding engagement with one another bymeans of the beforementioned encircling garter spring 294. The lower endportion of the push-pull rod 226 is threaded as shown at 298 and carriesthreaded thereon an annular stop nut 300. In operation, the annular stopnut 300 adjustably limits the downward movement of the push-pull rod 226by abutment thereof with the upper end of sleeve 302 which forms anupper extension of the beforementioned flanged supporting fixture 182.

Referring to the heretofore described apparatus, its operation is asfollows:

The tubular work piece 124 upon which the bellows forming operation isto be formed is first inserted vertically down through the opening 12 inthe top platform 10 and opening 131 in the collar portion of thefollower die 128 and lowered to the position shown in FIGURE 1 at whichits lower end rests upon the work elevator and indexing table 70 at acentered location surrounding the indexing guide pins 122 therein. Thetubular work piece 124, the external split die elements 146 and 147, theexternal follower die 128 and the internal expansion die segments 290,292, are then initially in the relative positions best shown in FIGURE5.

Next, fluid under pressure is introduced through port 214 into the upperend of the expansion die actuating cylinder 212 above the piston 218,thereby applying a downward force to the piston 218 and an equal andopposite upward force to the cylinder 212. The upward force from thecylinder 212 is transmitted upwardly through the supporting column 178to the expansion die carried supporting flange 238, and the downwardforce from the piston 218 is transmitted through the push-pull rod 226to the expansion die actuator wedge 230 which causes the expansion diecarrier sectors 242-264 the expansion die elements 266288 carriedthereby and the arcuate die segments 290, 292 to move radiallyoutwardly, initially to the position illustrated in FIGURE 6 at whichthe rounded outer edge of the expansion die segments 290, 292 makecontact with the inner surface of the tubular work piece 124 at a pointintermediate the external split dies 146 and 147, and the top of thefollower die collar 130. A slight circumferential bulge is thusinitiated at this point in the tubular work piece 124 as illustrated at304 in FIGURE 6. No axial movement is imparted to the expansion diesegments during the initial expansion movement.

Immediately following the commencement of the formation of the bulge 304in the tubular work piece --124,

simultaneous upward movement of the follower die 128 and the expansiondies 290, 292 is initiated. Such upward movement of the follower die iseffected by introduction of fluid under pressure through connections 68into the hydraulic actuators 50, 52, 54, and 56 at a controlled ratefrom a pressure source, not shown. The upward movement of the expansiondies are effected by energizing and controlling the speed of motor 206which drives the screw jacks 196 to impart upward movement to the frame190 which in turn imparts upward motion through the resilient supportingmeans 185 including springs 186 and air cushions 188, to the elevatorplatform 184 and thence through the supporting column 178 to theexpansion die assembly 180. The outward and upward movements of theexpansion die segments 290, 232 and the upward movement of the followerdie 128 are simultaneously continued until they reach the relativepositions shown in FIGURE 7 at which the convolution is thereby fullyformed in the work piece 124 as shown at 306. At this point, sufficientclamping force is applied upon the upper and lower surfaces of theconvolution 306 between the upper surface of the follower die collar 130and the lower surface of the split dies 146, 147, to insure completeformation of the convolution 306 in conformity with the shape of theexpansion die segments 290, 292 as shown in FIGURE 7.

Next, the follower die 128 is lowered sufliciently to remove theclamping pressure from the lower surface of the newly formed convolution306 as illustrated in FIG- URE 8, such lowering of the follower die 128being accomplished by introducing fluid under pressure throughconnections 66 and exhausting fluid from connections 68 of the hydraulicactuators 5056 at a controlled rate.

Next, following the initiation of the downward movement of the followerdie 128, the split die plates 138 and 140 are opened by actuation of thesplit die actuator jacks 157 and 159, thereby withdrawing the split dies146 and 147 from encirclement of the work piece 124, to the positionillustrated in FIGURE 9, leaving the work piece 124 then suspended bythe convolution 306 upon the internal expansion die segments 290, 292 asshown in FIGURE 9.

Next, the internal expansion die segments 290, 292 are retracted byintroduction of fluid pressure through port 216 and exhausting fluidfrom port 214 of the expansion die actuating cylinder 212, therebyapplying upward force to piston 218 which force is transferred throughthe push-pull rod 226 to the actuator wedge 230 thereby moving theactuator Wedge 230 upwardly, permitting the garter spring 294 to retractthe expansion die carrier sectors 242-264 radially inwardly on thedovetail guides 240 on the expansion die carrier supporting flange 238.This retraction of the expansion dies 290, 292 permits Lhe work piece124 to drop to a position in which it is iupporting upon the upper endof the follower die collar [30 by the previously formed convolution 306as shown 11 FIGURE 10.

Next, or preferably a short time prior to the beforelescribed retractionof the expansion die segments 290, I92 the motor 110 is actuated, whichthrough the inter- :onnecting chain and sprocket drive, simultaneouslyotates the elevator spindles 74, 76, 78 and 80 in a direcion which,through the action of the threaded nut bearngs 82-84 thereon raises theelevator table 70 upwardly nto supporting contact with the bottom end ofthe tubular vork piece 124. Upward movement of the table 70 is hencontinued until the work piece 124 is elevated a listance sufficient topermit the split dies 146 and 147 to re closed under the lower surfaceof the previously formed 'ellows convolution 306, as shown in brokenlines in FIG- JRE 11. Meanwhile, the downward movement of the ollowerdie 128 is continued until it reaches its lowermost osition, which isthe position it initially occupied as hown in FIGURES 1 and 5. At thispoint, the apparatus icluding the expansion dies 290, 292, split dies146 and .47, and follower die 128 are again in position in readiationcycle as beforedescribed.

ness for the commencement of the formation of another, succeedingbellows convolution by repetition of the form- These formation cyclesare sequentially repeated a number of times equal to the number ofaxially adjacent bellows convolutions desired to be formed in thetubular work piece.

An important feature of this invention resides in the prevention of anysubstantial rubbing or sliding action at the areas of forceful contactbetween the die members and the work piece at any time during theconvolution formation cycle or thereafter. This is accomplished by thehereinbefore described controlled relative movements of the dies, suchthat from the beginning of the formation of the bellows convolution asshown at 304 in FIGURE 6 to the completion thereof as shown in FIGURE 7,both the follower die 128 and the expansion die segments 290, 292 movesimultaneously upwardly relative to the split die elements 146, 147 theexpansion die segments 290, 292 moving upwardly as the convolution foldis formed at a rate which is approximately one-half the rate of upwardmovement of the follower die 128. Thus, the point of forceful contact ofthe rounded ends of the expansion die segments 290, 292 with the insidesurface of the tubular work piece 124 remains substantially fixed inposition thereon, and, likewise, the restraining contact of the exteriorsurface of the work piece 124 with the bore 131 of the follower die 128during the convolution forming cycle also remains substantially fixedrelative to one another. Thus, substantially all rubbing movementsbetween the contacting surfaces of the dies and the work piece areeliminated.

The regulation of the relative vertical movements of the expansion diesegments 290, 292, and follower die 128 to correspond precisely to thatwhich would result in their having no sliding movement relative to thesurface of the work piece 124 as the convolution is formed, would bedifficult, if not impossible to accomplish, because the axial movementof the work piece material within and adjacent the bellows convolutionbeing formed is a complex and possibly unpredictable function of theform, size and shape of the convolution being formed and the thicknessand physical characteristics of the material involved. Thus, therequired relationship between the axial movements of the expansion diesegments 290, 292 and follower die 128 is so complex as to beimpracticable of complete positive control.

To overcome the foregoing difliculty in controlling the relative axialmovements of the dies, the expansion assembly is elevated ashereinbefore described by the jacks 196, and the follower die 128 issimultaneously elevated by pistons 60 of the four hydraulic actuators50, 52, 54 and 56 during the convolution formation cycle, at rates whichonly approximate that necessary to accomplish the beforedescribedrelative movements. Any discrepancy between the thus controlled rates ofaxial movement between the expansion die segments 290, 292 and followerdie 128 is accommodated automatically by limited variation in axialmovement of the supporting column 178 and the expansion die mechanism180 carried thereby, permitted by the floating effect of the resilientsupporting means 185, which as beforedescribed, includes the springs 186and air cushions 188 positioned between the supporting plate 184 and therectangular elevator frame 190 which is in turn supported on the jackscrews 192 of the jacks 196. Thus, once the bellows convolution bulge iscommenced as shown at 304 in FIGURE 6, there is sufiicient resiliency inthe supporting means to permit the expansion die 290 to remain at afixed point of contact upon the inner surface of the work piece 124 asthe convolution fold progresses.

The upper and lower limits of travel of the elevator frame is controlledas required by the limit switch 209, by adjustment of the positions ofstops 215 and 217.

The resiliency of the resilient supporting means 185 between therectangular frame 190 and the supporting 9 plate 184, and also thespacing therebetween may be varied to some extent by variation of fluidpressure, preferably air pressure, introduced into the air cushions 188through the inlets 187, 189. In this manner, changes in size of toolingor other weight influencing factors can be accommodated.

The hereinbefore described apparatus and the method of operation thereofhas proved to be advantageous in making it possible to go to greaterextremes than heretofore possible with respect to the ratios of radialdepth to axial spacing and tightness of the bellows convolutions formed,also to hold closer and consistently repeatable dimensional tolerancesas well as to result in generally superior products in respect tofreedom from detrimental mam'ng, bumishing, scratching and injuriouscold working and thinning of the work materials. These advantages havebeen found to extend to the forming of bellows of a wide range of sizesfrom medium to large diameter in the order of 50 inches.

It is to be understood that the foregoing is illustrative only and thatthe invention is not limited thereby, but may include variousmodifications and changes made by those skilled in the art within thescope of the invention as defined in the appended claims.

What is claimed is:

1. In a machine for forming bellows from tubular stock, apparatuscomprising:

supporting and positioning means for such tubular stock;

a first die means positioned for restraining encirclement of a firstcircumferential portion of the external surface of such tubular stock;

a second die means positioned for restraining encirclement of a secondcircumferential portion of the external surfaces of such tubular stock,said first die means and second die means being spaced-apart relative toone another axially of such tubular stock;

means mounting said first and second die means for limited movementrelative to one another, axially of such tubular stock;

a third die means having a rigid, external, peripheral portionpositioned for encirclement thereof by such tubular stock at a locationaxially intermediate said first and second die means;

means for moving said peripheral portion of said third die meansgenerally radially outwardly into forceful engagement with the internalencircling surface of such tubular stock, to form an outwardcircumferential bulge in such tubular stock extending between said firstand second die means;

and means for simultaneously continuing such movement of said peripheralportion of said third die means generally radially outwardly, and suchmovement of said first and second die means relatively toward oneanother axially of such tubular stock, until completion thereby of anoutwardly projecting, circumferentially extending convolution in thewall of said tubular stock intermediate said first, second and third diemeans.

2. In a machine for forming metal bellows from tubular metal stock,apparatus comprising:

means for positioning such tubular stock in said machine;

a first die means positioned for restraining encirclement of a firstcircumferential portion of the external surface of such tubular stock;

a second die means positioned for restraining encirclement of a secondcircumferential portion of the external surfaces of such tubular stock,said first die means and second die means being spaced-apart relative toone another axially of such tubular stock;

means mounting said first and second die means for limited movementrelative to one another, axially of such tubular stock;

a third die means having a rigid, external, peripheral portionpositioned for encirclement thereof by such tubular stock at a locationaxially intermediate said first and second die means;

means mounting said third die means for limited movement relative tosaid first and second die means axially of such tubular stock;

means for moving said peripheral portion of said third die meansgenerally radially outwardly into forceful engagement with the internalencircling surface of such tubular stock, to form an outwardcircumferential bulge in such tubular stock extending between said firstand second die means;

and means for simultaneously continuing such movement of said peripheralportion of said third die means generally radially outwardly, and suchmovement of said first, second and third die means relatively towardeach other axially of such tubular stock, until completion thereby of anoutwardly projecting, circumferentially extending convolution in thewall of said tubular stock intermediate said first, second and third diemeans.

3. In a machine for forming metal bellows from tubular metal stock,apparatus comprising:

supporting means for such tubular stock;

a first die means positioned for restraining encirclement of a firstcircumferential portion of the external surface of such tubular stock;

a second die means positioned for restraining encirclement of a secondcircumferential portion of the external surfaces of such tubular stock,said first die means and second die means being spaced-apart relative toone another axially of such tubular stock;

means mounting said first and second die means for limited movementrelative to one another, axially of such tubular stock;

a third die means having a rigid, external, peripheral portionpositioned for encirclement thereof by such tubular stock at a locationaxially intermediate said first and second die means;

means mounting said third die means for limited movement of saidperipheral portion thereof relative to said first and second die meansaxially of such tubular stock;

means for movement of said peripheral portion of said third die meansgenerally radially outwardly into forceful engagement with the internalencircling surface of such tubular stock, to form an outwardcircumferential bulge in such tubular stock extending between said firstand second die means;

and means for simultaneously continuing such movement of peripheralportion of said third die means generally radially outwardly, and suchmovement of said first and second die means relatively toward oneanother axially of such tubular stock and maintaining said peripheralportion of said third die means at said location intermediate said firstand second die means, until an outwardly projecting, circumferentiallyextending convolution is completed in the wall of said tubular stockintermediate said first, second and third die means without substantialsliding movement of said first, second, and third die means axially uponthe surfaces of such tubular stock at the areas of contact therebetween.

4. In a machine for forming metal bellows from tubular metal stock,apparatus comprising:

I 3 limited movement relative to one another, axially of such tubularstock;

a third die means having a rigid, external, peripheral portionpositioned for encirclement thereof by such tubular stock at a locationaxially substantially midway between said first and second die means;

means mounting said third die means for limited movement of saidperipheral portion relative to said first and second die means axiallyof such tubular stock;

means for movement of said portion of said third die means into forcefulengagement with the internal encircling surface of such tubular stock,to form an outward circumferential bulge in such tubular stock extendingbetween said first and second die means;

and means for simultaneously continuing such movement of said third diemeans, and for moving said first and second die means relatively towardone another axially of such tubular stock and maintaining said portionof said third die means at said location between said first and seconddie means until completion of an outwardly projecting, circumferentiallyextending convolution in the wall of said tubular stock intermediatesaid first and second die means and said portion of said third diemeans,

said movements being without substantial sliding movement of said firstand second die means and said portions of said third die means axiallyupon the surface of such tubular stock at the areas of contacttherebetween.

5. In a machine for forming metal bellows from tubular metal stock,apparatus comprising:

supporting means for positioning such tubular stock in said machine;

a first die means positioned for restraining encirclement of a firstcircumferential portion of the external surface of such tubular stock;

a second die means positioned for restraining encirclement of a secondcircumferential portion of the external surfaces of such tubular stock,said first die means and second die means being spaced-apart relative toone another axially of such tubular stock;

means mounting said first and second die means for limited movementrelative to one another, axially of such tubular stock;

a third die means having a rigid, external, peripheral portion movabletransversely between retracted and extended positions and positioned forencirclement thereof by such tubular stock at a location axiallyintermediate said first and second die means;

power means for moving said portion of said third die means between saidretracted and extended positions relative to said internal encirclingsurface of such tubular stock extending between said first and seconddie means;

means for moving said first and second die means relatively toward oneanother axially of such tubular stock simultaneously with transversemovement of said portion of said third die means towards such extendedposition for forming an outwardly projecting, circumferentiallyextending convolution in the portion of the wall of such tubular stocklocated intermediate said first and second die means;

means included in said power means for retracting said portion of saidthird die means clear of such convolution following the formationthereof;

and means for moving said supporting means a predetermined distanceaxially of such tubular stock, following said retraction of said portionof said third die means, for positioning such tubular stock forformation of another convolution axially adjacent the first-mentionedconvolution.

6. In a machine for forming metal bellows from tubular metal stock,apparatus comprising:

supporting means for positioning such tubular stock in said machine;

a first die means movable between transversely open and closedconditions and positioned for close encirclement of a firstcircumferential portion of the external surface of such tubular stockwhen closed;

a second die means positioned for close encirclement of a secondcircumferential portion of the external surfaces of such tubular stock,said first die means and second die means being spaced-apart relative toone another axially of such tubular stock;

means mounting said first and second die means for limited movementrelative to one another, axially of such tubular stock;

a third die means having a rigid, external, peripheral portion movablebetween transversely retracted and extended positions and positioned forencirclement thereof by such tubular "stock at a location axiallyintermediate said first and second die means;

power means for moving said portion of said third die means between saidretracted and extended positions relative to said internal encirclingsurface of such tubular stock extending between said first and seconddie means;

means for moving said first and second die means relatively toward oneanother axially of such tubular stock simultaneously with movement ofsaid portion of said third die means toward said extended position forforming an outwardly projecting, circumferentially extending convolutionin the wall of such tubular stock located intermediate said first andsecond die means;

means for moving said first die between said open and closed conditionsto permit, when in opened condition, passage axially therethrough of aconvolution formed in such tubular stock as aforesaid;

and means for moving said supporting means a predetermined distanceaxially of such tubular stock for moving such stock and a previouslyformed convolution therein through said first die means as aforesaid andfor positioning such tubular stock for formation of another convolutionaxially adjacent the first-mentioned convolution.

7. In a machine for forming bellows from tubular stock, apparatuscomprising:

supporting and positioning means for such tubular stock;

a first die means positioned for restraining encirclement of a firstcircumferential portion of the external surface of such tubular stock;

a second die means positioned for restraining encirclement of a secondcircumferential portion of the external surfaces of such tubular stock,said first die means and second die means being spaced-apart relative toone another axially of such tubular stock;

means mounting said first and second die means for limited movementrelative to one another, axially of such tubular stock;

a third die means having a rigid, external, peripheral portionpositioned for encirclement thereof by such tubular stock at a locationaxially intermediate said first and second die means;

supporting means supporting said third die means including saidperipheral portion thereof for limited movement relative to said firstand second die means axially of such tubular stock, said supportingmeans including a resilient coupling between said third die means and atleast one of said first and second die means permitting said third diemeans limited freedom for axial movement relative thereto;

and means for moving said peripheral portion of said third die meansinto forceful engagement with the internal encircling surface of suchtubular stock, to form an outward circumferential bulge in such tubularstock extending between said first and second die means and saidperipheral portion of said third die means.

8. In a machine for forming metal bellows from tubular metal stock,apparatus comprising:

supporting means for such tubular stock;

a first die means positioned for restraining encirclement of a firstcircumferential portion of the external surface of such tubular stock;

a second die means positioned for restraining encirclement of a secondcircumferential portion of the external surfaces of such tubular stock,said first die means and second die means being spaced-apart relative toone another axially of such tubular stock;

means mounting said first and second die means for limited movementrelative to one another, axially of such tubular stock;

a third die means having a rigid, external, peripheral portionpositioned for encirclement thereof by such tubular stock at a locationaxially intermediate said first and second die means;

means supporting said third die means including said peripheral portionfor limited movement relative to said first and second die means axiallyof such tubular stock, said means including axially resilient couplingmeans between said third die means and at least one of said first andsecond die means for permitting said third die means to remain at saidlocation axially intermediate said first and second die means;

means for moving said peripheral portion of said third die meanstransversely into forceful engagement with the internal encirclingsurface of such tubular stock, to form an outward circumferential bulgein such tubular stock extending between said first and second die means;

and means for simultaneously continuing such movement of said portion ofsaid third die means, and moving said first and second die meansrelatively toward one another axially of such tubular stock,

thereby permitting formation of an outwardly projecting,circumferentially extending convolution in the wall of said tubularstock intermediate said first and second die means and said peripheralportion of said third die means without substantial sliding movement ofsaid first and second die means and said peripheral portion of saidthird die means axially on the surfaces of such tubular stock at theareas of contact therebetween.

9. In a machine for forming bellows from tubular stock,

apparatus comprising:

supporting and positioning means for such tubular stock;

a first die means positioned for restraining encirclement of a firstcircumferential portion of the external surface of such tubular stock;

a second die means positioned for restraining encirclement of a secondcircumferential portion of the external surfaces of such tubular stock,said first die means and second die means being spaced-apart relative toone another axially of such tubular stock;

a third die means having an external, peripheral portion positioned forencirclement thereof by such tubular stock at a location axiallyintermediate said first and second die means;

means for moving said peripheral portion of said third die means intoforceful engagement with the internal encircling surface of such tubularstock, to form an outward circumferential bulge in such tubular stockextending between said first and second die means;

and means for imparting a predetermined movement of said third die meansrelatively toward one of said first and second die means axially of suchtubular stock, while simultaneously continuing such expansion of saidperipheral portion of third die means, said means for imparting saidpredetermined movement including resilient coupling means permittingmovement of said third die means which departs limitedly axially fromsaid predetermined movement,

thereby forming an outwardly projecting, circumferentially extendingconvolution in the wall of said tubular stock intermediate said firstand second die means and said peripheral portion of said third die meanswithout substantial sliding movement of said peripheral portion of saidthird die means axially relative to the surface of such tubular stock'at the point of contact therebetween.

10. In a machine for forming bellows from tubular stock, apparatuscomprising:

a supporting structure including an upper platform having an openingtherein for encircling a tubular work piece positioned verticallytherethrough;

a lower platform vertically, slidably supported in said structure, forsupporting and elevating such tubular work piece;

an intermediate supporting means vertically slidably supported in saidstructure intermediate said upper platform and said lower platform;

a first external die means including die elements slidably supported onsaid upper platform for movement transversely between open and closedpositions, said die means being adapted closely to encircle the exteriorof such tubular work piece when closed and to clear the externaldiameter of convolutions formed in said tubular work piece when opened;

a second external die means carried on said intermediate supportingmeans and having an opening therein coaxial with said first-mentionedopening for closely encircling the exterior of such tubular work piece;

an interior expansion die means supported in said supporting structurein position to be encircled by such tubular work piece, and including arigid, expansion die element expandable generally radially into forcefulContact with the interior surface of such tubular work piece, axiallyintermediate said first and second external die means;

vertically movable carrier means for supporting said expansion die meansas aforesaid, said carrier means including power means carried therebyfor applying such expanding movement to said expansion die element;

means supporting said vertically movable carrier means and said powermeans, including means for imparting controlled vertical movementthereto relative to said supporting structure, thereby to impartcontrolled vertical movement to said expansion die means relative tosaid first and second die means;

means for imparting controlled vertical movement to said intermediatesupporting means relative to said supporting structure;

and means for imparting controlled vertical movement to said lower tablerelative to said supporting structure.

11. Apparatus according to claim 10 in which said means supporting saidvertically movable carrier means includes resilient coupling meansbetween said means supporting said vertically movable carrier means andsaid means for imparting controlled vertical movement thereto,permitting limited departure in vertical movement of said expansion diemeans from such controlled movement.

12. A method of forming bellows convolutions in a tubular work piececomprising:

applying circumferentially extending, radial restraint to the exteriorsurface of such tubular work piece at two, axially spaced-apartlocations thereon;

expanding a circumferentially extending rigid forming body radiallyagainst the interior surface of said work piece axially intermediatesaid two spaced-apart locations, and thereby forming a circumferential,radially outwardly extending bulge in the wall of said work piecetherebetween; and moving said forming body axially relative to saidaxially spaced-apart locations such as to maintain the areas of mutualcontact of said forming body and applying circumferentially extending,radial restraint to said interior surface of said work piecesubstantially the exterior surface of said tubular work piece at freefrom axial sliding motion relative to one another two axiallyspaced-apart, exterior locations thereon; while continuing expanding ofsaid forming body, applying a rigid forming body to the interior surfaceof and thereby increasing the radially outwardly eX- said work piecealong an interior circumferentially tending depth of said bulge.extending contact area axially intermediate said 13. A method of formingbellows convolutions in a spaced-apart locations, with sufiicient forceto form tubular work piece comprising: an initial annular, radiallyoutwardly extending bulge applying circumferentially extending, radialrestraint to in the wall of said work piece intermediate said theexterior surface of such tubular Work piece at spaced-apart exteriorlocations; two, axially spaced-apart locations thereon; and moving saidtwo axially spaced-apart exterior locaexpanding a circumferentiallyextending rigid forming tions and said interior contact area of saidbody body radially against the interior surface of said relativelyaxially toward each other to reduce the work piece, axially intermediatesaid two spacedapart locations, and thereby forming a circumferential,radially outwardly extending bulge in the wall axial spacingstherebetween while continuing application of said expanding force andthe resulting continuing radially outwardly deepening of said bulge.

of said work piece therebetween;

and moving said forming body axially relative to said axiallyspaced-apart locations such as to maintain the areas of mutual contactbetween said forming References Cited by the Examiner UNITED STATESPATENTS body and said interior surface of said work piece and 2,306,0181 4 Fentress 72-59 between the exterior surface of said work piece d2,353,253 7/ 1944 Llvermont 72-399 said spaced-apart locations thereonsubstantially free 2,756,804 9 6 sChmdler et a1 72-59 from axialdisplacement relative to said interior and 2,773,538 959 De Mers 72 59exterior surfaces while continuing the expansion of 2,960,142 11/1960CIm ChOWSkI 72-62 Said forming body and the resultant increasing of the3,130,771 4/1964 Peyton 7259 radially outwardly extending depth of saidbulge, to form a completed bellows convolution. 14. A method of formingbellows convolutions in a tubular work piece comprising:

CHARLES W. LANHAM, Primary Examiner.

A. L. HAVIS, E. M. COMBS, Assistant Examiners.

1. IN A MACHINE FOR FORMING BELLOWS FROM TUBULAR STOCK, APPARATUSCOMPRISING: SUPPORTING AND POSITIONING MEANS FOR SUCH TUBULAR STOCK; AFIRST DIE MEANS POSITIONED FOR RESTRAINING ENCIRCLEMENT OF A FIRSTCIRCUMFERENTIAL PORTION OF THE EXTERNAL SURFACE OF SUCH TUBULAR STOCK; ASECOND DIE MEANS POSITIONED FOR RESTRAINING ENCIRCLEMENT OF A SECONDCIRCUMFERENTIAL PORTION OF THE EXTERNAL SURFACES OF SUCH TUBULAR STOCK,SAID FIRST DIE MEANS AND SECOND DIE MEANS BEING SPACED-APART RELATIVE TOONE ANOTHER AXIALLY OF SUCH TUBULAR STOCK; MEANS MOUNTING SAID FIRST ANDSECOND DIE MEANS FOR LIMITED MOVEMENT RELATIVE TO ONE ANOTHER, AXIALLYOF SUCH TUBULAR STOCK; A THIRD DIE MEANS HAVING A RIGID, EXTERNAL,PERIPHERAL PORTION POSITIONED FOR ENCIRCLEMENT THEREOF BY SUCH TUBULARSTOCK AT A LOCATION AXIALLY INTERMEDIATE SAID FIRST AND SECOND DIEMEANS; MEANS FOR MOVING SAID PERIPHERAL PORTION OF SAID THIRD DIE MEANSGENERALLY RADIALLY OUTWARDLY INTO FORCEFUL ENGAGEMENT WITH THE INTERNALENCIRCLING SURFACE OF SUCH TUBULAR STOCK, TO FORM AN OUTWARDCIRCUMFERENTIAL BULGE IN SUCH TUBULAR STOCK EXTENDING BETWEEN SAID FIRSTAND SECOND DIE MEANS; AND MEANS FOR SIMULTANEOUSLY CONTINUING SUCHMOVEMENT OF SAID PERIPHERAL PORTION OF SAID THIRD DIE MEANS GENERALLYRADIALLY OUTWARDLY, AND SUCH MOVEMENT OF SAID FIRST AND SECOND DIE MEANSRELATIVELY TOWARD ONE ANOTHER AXIALLY OF SUCH TUBULAR STOCK, UNTILCOMPLETION THEREBY OF AN OUTWARDLY PROJECTING, CIRCUMFERENTIALLYEXTENDING CONVOLUTION IN THE WALL OF SAID TUBULAR STOCK INTERMEDIATESAID FIRST, SECOND AND THIRD DIE MEANS.